Multiple quick acting refrigerating



A.` scHwARz Re. 21,600

ULTIPLE QUICK ACTING HEFRIGERATING SYSTEM AND PROCESS oct. 1 5, 1940.

6 Sheets-Sheet 1 Original Filed April 2, 1932 .I l. Q l n W m W Nm. 4| uw R. m a m, o 1MM. A um Q. m6 m6 w Myx 1 A 1 wm. a Q .w 9. l, p nm. w I.' ww. w m mw l u u l Rw h l l.. N5 vx Mk k @lv Nw m. am l l. x

Oct. l5. 1940. v A, scHwARz MULTIPLE QUICK ACTING REFRIGERATING SYSTEM ANDl PROCESS Original Filed April 2, 1932 6 Sheets-Sheet 2 u-sl Schwarz,

o@ 15. 1940. SCHWARZ Re 21.600

HULTIPLE QUICK ACTING REFRIGERATING SYSTEM AND PROCESS original Filed April 2, 1932 e sheets-sheet s y JNVENTUE y U5U5T55HWAHZ 52'." M, @mm/x mw A'TTURNEKS.

Oct. ll5, 1940. A. scHwARz Re.y 21,600

HUTIPLE QUICK ACTING REFRIGRATING SYSTEM AND PROCESS original Filed April 2, 1932 s sheets-sheet 4v A. SCHWARZ NULTHIPLE QUICK ACTING REFRIGERATING SYSTEM AND PROCESS Original Filed April 2, 1932 6 Sheets-Sheet 5 JNVENTUR 7L/5 UST UHWAEZ M .L aM/m HTTUKNEYZS Od. 15, 1940. A SCHWARZ Re. 21,600

MULTIPLE QUICK GTING IREFRIGERA'IXNG SYSTEM AND PROCESS Original Filed April 2, 1932 6 Sheets-Sheet 6 Ressued Oct. 15, 1940 -UNITED STATES PATENT OFFICE -MULTIPLE QUICK ACTING REFRIGERATING SYSTEM AND PROCESS August Schwarz, Chicago, Ill,

41Claims.

The invention relates to multiple quick acting refrigerating systems and processes, and the object of the invention is to provide a refrigerating system consisting of a plurality of condensers, a

combination evaporator and condenser, a plurality of compressors, and a double evaporator, all these parts being connected with each other in such a manner that they may selectively be combined to operate as a one or multiple stage refrigerating system.

Another object of the invention is to provide a multiple refrigerating system having a double evaporator consisting of two sets of evaporator tubes which are arranged inrelation to each other .so that between said tubes a refrigerator pan or the like may be inserted, so that said pan is surrounded on all sides by evaporator tubes, giving vthe device a high eiilciency and quick action.

Another object of the invention is to provide apparatus whereby gas or any other iuid medium of high temperature may be condensedl or cooled in a plurality of steps to a very low temperature; and whereby instead of the ordinary two cooling mediums employed, three cooling mediums of 26 different temperature are employed, for example, water is employed in the first stage; obviously a medium colder than water such as brine or a refrigerant of high boiling point is used in the second stage, and inthe third or last stage brine 30 of suitable low temperature or a vaporized refrlgerant of suitable low boiling point is used as the inal cooling medium whereby the refrigerating machine capacity requirements employing the refrigerant of low boiling point will be much lower and in general the refrigerating power consumption by the proposed method will be much lower than by the two stage methods ernployed heretofore. `4

Still another object of myV invention consists in a novel process whereby compressed carbon dioxide gas or a gaseous refrigerant of low boiling point is cooled by water in the first stage, further cooled in a second stage by vaporization' of a refrigerant condensing at atmospheric lor much lower condenser pressure than the condenser pressure of the carbon dioxide or of the refrigerant of low boiling point, and whereby a portion of the carbon dioxide or low boiling point refrigerant is vaporlzed in a third stage to further cool the remaining portion to the desired low temperature.

A further object oi' my invention consists in a y novel process in cooling fluids of high temperature to a low temperature in three stages, by utilizingwaterasthecoolingmediuminthe iirst, and by vaporizing a refrigerant of suitable low boiling point at normal suction pressure as the second cooling medium, and vaporizing a portion of said refrigerant' in the third stage at very low suction pressure or by creating a vacli uum to obtain the desired 1ow temperature for A the nal cooling of the fluid medium.

Other objects of the invention not specifically' mentioned may be easily ascertained and understood from the following description in connection with the drawings forming a part thereof.

It is, however, to be understood that the invention is not to be limited or restricted to the exact formation and construction shown in the drawings and described in the.specication, but that said invention is only to be limited by the scope of the claims appended hereto. j

In the drawings illustrating a preferred embodiment of the invention- Figure 1 is a diagrammatical plan view of the refrigerating system according-to the invention.

Figure 2 is a combination condenser and evaporator unit used in connection with the present invention.

Figure 3 is a sectional view on line 3 3 of Figure 2, and

Figure 4 is a view similar to Figure 2, showing a double refrigerator used in connection with the present invention.

Figure 5 is a diagrammatic view of a portion 30 of the system shown in Figure 1, and illustrating one of the uses oi the system.

Figure 6 is a fragmentary diagrammatic view illustrating another use of the system. y

Figure '1 is still another fragmentary diagrammatic view illustrating the use of a portion of the system for condensing and cooling a refrigerant, and also for cooling of a iiuid medium.

Figure 8 is a fragmentary diagrammatic view of a portion of the system adapted for cooling of refrigerant gases or for cooling of other iiuids of high temperature to a low temperature.

'Ihe present inventionis a modification and improvement over my copending applications Serial No. 429,176 led February 1,7, 1930, Serial No. 445,390 iiledlApril 18, 1930, now matured into Patent No. 1,951,447, issued March 20, 1934, and Serial No. 601,262 filed March 25, 1932, now ma' tured into Patent No. 1,954,543, issued April 10, 1934.

In the multiple quick acting refrigerating system according to the present invention, a high pressure condenser or cooler 5 is provided which is cooled by fresh water entering the condenser through a pipe I by means of a pump 1, and

leaving the condenser through a pipe I. Any refrigerantmaybeusedinthishighpressure condenser, and is compressed by a compressor 2 from which it enters the high pressure condenser 5 through the pipes 21 and l". 'The liquid refrigerant leaves the high pressure condenser i through pipe I including a valve Il and a second pressure reducing valve II. by which it is introduced into a low pressure and low tempera.- ture condenser and liquid cooler I2. The interior of the low Vpressure and low temperature condenser and cooler I2 constitutes a closed tank or housing I 2n through which extend a plurality of condenser or cooler tubes 2 I. The refrigerant is discharged by expansion valve llinto a header 22 from which it enters condenser' tubes 2|,causing the pressure and temperature of the liquid refrigerant to be considerably reduced because of the low temperature present in condenser I2, as later explained.

If desired, both condensers. the high pressure condenser i and the low pressure condenser tubes 2|. may be operated at an equal pressure.

When the two units l and I2 are operatively connectedinseries,theunitlisacondenser and the unit I2 is a liquid cooler if a relatively high refrigerant pressure is maintained: the unit l is a gas cooler and the unit I2 is a condenser if a relatively low refrigerant pressure is maintained both umts may be condensers at diiferent pressures if the expansion valve II is partially closedtoeffectapressurereduction. Thetwo umts l and I2 are therefore variously designated as condensers or coolers depending on their use in diil'erent operative arrangements.

By condenser in the claims is meant condenser or cooler as the case may be' depending on operating conditions, for example the pressure of the refrigerant.

A second fresh water cooled condenser Il re celves'a compressed refrigerant. through a pipe l1". with valves Il and 52. from a second compressor Il. This refrigerant is drawn through a pipe 25, with a valve Il, oil' evaporator tubes Il which are arranged in the combination tank or housing I2n as illustrated, especially in Figures 2 and 3. 'I'he refrigerant is recompressed by the compressor I l. and is cooled in condenser Il by water supplied by a pump Il through a pipe I1. 'I'his cooling water is drained off by means of a pipe Il. The liquid refrigerant from the second -fresh water cooled condenser I2 nows through a pipe I9 and an expansion valve 2l into the evaporator tubes I of the combination tank or housing I2l where the refrigerant cools the refrigerant which is present in the condenser tubes 2|: thereby the pressure and temperature is lowered further. Interposed in the pipe I2 are l three spaced valves I5, and l1.

The combination unit I2 is provided at its four sides respectively with header manifolds 22, 22, 24 and 25, so arranged that the condenser tubes 2| connect the manifolds 22and 22 with each other and the evaporator tubes Il the manifolds 2l and 2l.

y A double refrigerator or evaporator 2l, forming a chamber or housing which may be closed entirely or may be open on top, contains two sets of evaporator tubes 21 and 22, respectively. Prom the header manifold 2l, the liquid refrigerant present in the tubes 2l o'f the combination unit I2 flows through pipesv21 and 2l and ex-` pansion valves l2 and 2! into the evaporator tubes 21' and 2ln of the double refrigerator or evaporator 2i, where said refrigerant evaporates.

From these evaporator tubes. the refrigerant vapor is drawn of! through a pipe 2l and recompressed by the compressor I and then returned through pipesv I1 and 2* into the high pressure condenser l. The refrigerant vapor in the evaporator tubes 21 in tank 2l is drawn off through apipe 2| and recompressed by a compressor 20 and is returned to the high pressure condenser l through the pipes 22 and l* from where the refrigerant is forced through the pipe I0 into the low pressure and low temperature condenser and cooler tubes 2| of combination unit I2, through pipe 21, and expansion valve 62 back into the evaporator tubes 21n where it is vapor-ized again. The two refrigerating circuits described above and using the two sets of evaporator tubes 21 and 2l* may be used simultaneously. In that case. the refrigerant drawn olf by compressor s and the refrigerant from the compressor will meet in the pipe I* before entering the high pressure condenser l.

Instead of drawing ofi and recompressing the refrigerant vapor` in the tubes 21* by compressor 2l and the vapor in the evaporator tubes 2ll by compressor 'l as described above, the contents of both setsA of tubes can be drawn off and recompressed by either one of said two compressors. The manner of doing this will be described later on.

If desired, the combination unit I2 may be eliminated by closing expansion valve II and a valve I2 arranged in pipe 21 adjacent said unit. the expansion valve 2l in pipe Il, and the valve Il in pipe 25 through which the compressor Il draws oil.' the refrigerant vapor from the evaporator tubes I l.

When these valves are closed and the unit I2 is eliminated, the refrigerant vapor in the evaporator tubes 2lIl of the evaporator 28 will be drawn olf through the pipe 22 by the compressor ,I and will be recompressed by said compressor and forced through pipes I1, 21h and 21'l into the second fresh water cooled condenser I2, and in this event valves 38, Il, 4I in pipe I6, valves II, I2, Il, and Il in pipes 31, 31 and I1", valves Il, II, and I1 in pipe I9, valves ll and 49 in pipe Il, and the expansion valve 22 in pipe 22 must be open. 'I'he valves 5I and l2 in pipes 21 and 21'* and valves Il in pipe 2l must be closed, and thereby the circuit between the compressor l. the condenser I2, and the evaporator 26 is com- When, as mentioned above, the combination unit I2 is eliminated, a refrigerant circuit may be established and used between the compressor 3l. the high pressure condenser 5, and the evaporator tubes 21'* of the evaporator 22.

To accomplish this, the valves Il and in the pipe line 2|, the valves 5I and 51 in the pipe line 22, valve l2 in pipe 9*, valve 5l in pipe Il, valves Il and ll in pipe 62, and the expansion valve l2 must be open, while the valve M in pipe Il which connects the pipe 2l with the pipe, the valvel il in pipe 21, the valve 6l inthe bypath B1 connecting pipes 9* and Ill, the valve il in pipe 21, and the valves I2 in `pipe2l must be closed.

When, as stated above. either one of the two compressors 9 or 20 is to be used in connection with the two sets of evaporator tubes 21* and 22l of the evaporator 28, 'it is only necessary to open or close some of the above mentioned valves. If, for instance, the compressor 2 is to be used, the valve Il in pipe line 2l is closed, whilethe valves Il. Il, Il, Il, and l are open. If, however, the

compressor Il is'to be used. the valve 35 is to be closed, and the valves 35, 54, 54 and 55 are to be open. y

'I'he bypath 51, connecting the pipe 5* and the pipe Il may be used, if desired, to elimi'nate the high pressure condenser 5. To accomplish this,

` the valves 59, 59, and 6II must be closed, while the valve 66 must be open. By eliminating the high pressure condenser. power is saved, because the resistance in the high pressure condenser is removed. 'I'he bypaths, however, should only be utilized after the temperature-and the suction pressure in the double evaporator 25 have been lowered.

If desired, the double evaporator 26 may be eliminated, and then the combination condenser and evaporator I2 may be used as a double refrigerator or evaporator in connection with the two water cooled condensers and I3 respectively.

In order to do this, the tubes 2| in the combination unit I2 must be emptied, and this is done in the following manner: The expansion valve II and the valves 54, 69, 49, and 42 are closed. One of the bypaths`69' leading from pipe 21 to pipe 3| is then opened, and thev liquid refrigerant in the condenser tubes 2| is drawn oiI and recompressed by means of the compressor 3|) and goes through the following pipe line: pipe 21, bypath 59, pipe 3|, compressor 3|I, pipe 32, pipe 9, high pressure condenser 5, pipe I0, pipe 52, pipes 21 and 29. A part of said refrigerant enters the evaporator tubes 21 through the expansion valve 53, the other portion enters `the evaporator tubes 28' through the expansion valve 29. The latter part is drawn off and recompressed by compression 9 and returned to the condenser 5. 'Ihe first part is cooled and liquefied by the last mentioned part, and collected in the evaporator tubes 21 from where it cannot escape, since the valve 54 is closed. In this manner, the condenser pipes 2| are emptied. After that is don'e, the valves 48, 6|I, 6B, and 5| are closed.

The evaporator tubes I5 in the combination unit I2, the fresh Water cooled condenser I3 and the compressor I4 are connected and operate together as described before, so that any liquid refrigerant entering the emptied tubes 2| from the high pressure condenser 5 evaporates in these tubes. The refrigerant vapor in the tubes 2| is drawn oiI and recompressed and returned to the condenser 5 by compressor 30 through the bypath 59 and the pipes 32 and 9. In this manner, both sets of -tubes in the unit I2 are being used as evaporator tubes, and said tank is actually acting as a double evaporator as illustrated in Figure 5.

A fluid medium may be conducted either from the double evaporator 26 or from the combination unit I2 through a cooling room 19 by any suitably and conveniently laid out pipe line. For instance, if the unit is used as avcombination evaporator and condenser, a brine solution can be forced by means of a brine pump 1I through a pipe 12 into and through the cooling room 19 and from there through pipes 13 and 14, combination unit I2, pipe 15, the double evaporator 26, and the pipe 15 back to the pump 1I. By`conducting the brine through this pipe line, the brine coming from the cooling room will be cooled in thev combination unit I2 so that the brine solution will return to the double evaporator 26 at a reduced temperature. While the brine solution iiows through unit I2, it will be cooled by the vaporized refrigerant in the evaporator tubes-I5.

'Ihe evaporator tubes 21* of the double evaporator 26 which are shown in Figure 4 as extending vertically are preferably arranged at a` distance from each other greater than the distance between the horizontal extending evaporator tubes thereby a rectangular' opening is obtained between adjacent and crosswlse extending evaporator tubes, and these openings are adapted to receive refrigerator pans whichwill be surrounded entirely by evaporator tubes so that liquid or any substance in these refrigerator pans may be frozen solidly in a comparatively short time.

Recapitulating. it will be evident that the multiple system is capable of numerous adjustments to satisfy widely varying operating conditions.

Thus, the units 5 and I2 may be utilized in series, or the unit 5 may be eliminated by means of the by-pass line 51.

Similarly, the unit I2 may be eliminated by means of the by-pass line 62. If desired, part of the liquid refrigerant from the condenser 5 may pass through the by-pass line 62 and the remaining portion may be directed through the unit I2 to the line 21.

Regardless of how the units 5 and I2 are connected in the.system, either or both of the elements 21EL and 28* in the double evaporator may be utilized. For the spent gases from the evaporator 26, either or both of '30 may be employed.

'I'he two watercooled condensers 5 and I3 mayl the compressors 9 and 21, the line 3|, the compressor 3D and the lines 32 and 9I back to the condenser. The other circuit proceeds from the condenser I3 through the lines I9, 50 and 28, the expansion valve29, the tubes 28, the line 35, the compressor 9 and the lines 31, 31h and 31L back to the condenser. Utilization of two single stage systems with the condensers in this case constitutes a double evaporator, is specifically illustrated in Figure 5.

All of the foregoing arrangements are possible in the plant as illustrated in Figures 1 and 6. Figure l shows the plant as adapted for the cool- 5 and I3 for cooling the unit I2, which ing of brine or other equivalent medium. Figure 6 diiers in that it illustrates the plant as adapted for the quick freezing of ice or other commodity in the refrigerator 26.

The system may also be adapted for the cooling of liquid refrgerant/ for outside use. Such arrangement is illustrated in Figure 7 wherein the refrigerant is compressed in either or both of the compressors 9 and 30, then condensed in 5- and further cooled in I2 or, if directed through the v by-pass 51, condensed in the unit I2 which is cooled by expanding refrigerant'. The cold liquid refrigerant may be taken off through the line 21 for outside use.v Additional refrigerant may be supplied to t-he system through the line 59.

Figure 8 illustrates the system as adapted for the cooling of a fluid medium in` three stages by utilizing three diii'erent cooling mediums of different temperature to cool the iiuid to a very low temperature for outside use; or for example a refrigerant may be cooled as a preliminary step in the production of solid CO: (dry ice). Liquid refrigerant from the condenser 5 and the unit I2 enters the line 21 and then splits, one portion being vaporized in the tubes 2l', andthe other portion passing through the fully opened valve into the tubes 21* where it is further cooled by the vapor in the tubes 2l.- Where the system is to be employed for the purpose just mentioned, a closed Ytutes the carbon dioxide cooling element. 'Ihe IN I cooled carbon dioxide of low temperature coming from cooler I2 passes through conduit 21 which communicates with cooling unit 26. Conduit 21 is provided with a branch line 28 which communicates with the evaporator tubes located in the cooling unit 26 and pipe 28 is provided with an expansion valve 29.

A portion of the low temperature carbon dioxide flowing through conduit 21 enters the unit 2l through the open valve 62 while another portion pases through the expansion valve 29. The cooled liquid refrigerant from unit 26 may be taken oi! for outside use through conduit SI, as disclosed in Figure 8, while the low temperature exhaust in the evaporator tubes may be taken oil from unit 26 by compressor 9 and directed by connection II* into by-pass 61 from whence it is directed into cooler I2. Additional gases may be taken in on the suction side of compressor 30 and directed by means of conduit 32 into the fresh water condenser l, thence into cooler I2, or by means of conduit 61 into cooler I2, where the additional gas is made to mingle with the exhaust. Any suitable pressure, either high or low,

may be employed. If desired, the refrigerant from the condenser I3 may be split, where the system is to be used for refrigerating purposes only, one part going to the unit I2 through line Il and the other part passing through the lines I9, l and 2l, the tubes 2l* in unit 2i and the lines 36, 31 and 31h and 31` back to the condenser I2. The cold liquid refrigerant from the tubes 21' may be withdrawn through the line 3| foroutside use. To replace liquid so withdrawn, additional refrigerant may be supplied to the system at the inlet of the compressor 30 and then to the condenser I. The gaseous refrigerant from the tubes 22 is recompressed. The refrigerant in the tubes 2l* is drawn oil by the compressor 9 and may be directed either to the condenser or to the bypass line 81 through a connection I I* between the lines I1 and 61 as shown in Fig. 8. If a liquid is to be introduced for the purpose of chilling, it may be introduced through pipe 22 directly into condenser or cooler 5, through units I2 and 2l. If desired, a cooling medium, for Aexample water, may be employed in condenser E; vaporized ammonia.or brine may be utilized in unit I2; and ammonia may beutilized in unit 26. It may be understood if ammonia or similar refrigerant is used in units I2 and 26, a lower suction pressure or vacuum is maintained in unit 26 than in unit double evaporator 2l, may be led through pipe Il (which is connected with pipe 28) to the junction with pipe Il and allowed to mingle with the liquid refrigerant coming from condenser I2, before passing through expansion valve 2li. The vaporized refrigerant is drawn from the evaporator tubes in unit I2 by compressor I4 and returned to the fresh water cooled condensers I3. The refrigerant vaporized in double evaporator 26 is returned to the fresh water cooled condensers 5 and I2 by either compressor l or III or both.

The fresh water cooled condenser Il may be disconnected from the system and liquid refrigerant from the pipe 2l may be returned to unit I2 in the same manner as heretofore defined.

In this event only the part ofthe refrigerant returned as just described is vaporized by expansion valve inthe evaporator tubes in unit I2 and the exhaust is drawn off by compressor Il and returned to the fresh water cooled condenser 5 by means of pipe lines 31, 21 and 9; it being understood that valve M and valve l1 under these conditions are closed and valves 24, I3, 42, 41 and 49 must be open.

lfde'sired condenser I3, compressors 20 and 9 may be disconnected, and liquid refrigerant from unit I2 may be expanded by expansion valve B3 into one path of the double evaporator 2B, the exhaust then directed vby means of pipe line 3i and into the other path of said evaporator unit and valve Il used to drop the suction pressure, the exhaust being made to iiow in counterdirection to its usual now and returned through open expansion valve 29 into pipe 28, by-pass 50, through expansion valve 2II through a second path in unit I2 to compressor, Il and by means of pipe line 31h and l* and thence into condenser 5 and into cooler I2.

In order to have the refrigerant flow through the circuit just described, it will be understood that valves B3, I5, 29, II, l1, I1 and M must be closed, as must also valves and 6 I.

I am, of course, aware that many changes in the details of construction of units I2 and 26 and relative arrangements of parts, steps, and arrangements of apparatus may be different from the disclosure as given for purposes of illustration. I do not, therefore, desire to be strictly limited to this disclosure as given for purposes of description but rather to the scope of the appended claims.

Having described my invention and how the same is to be used, I claim as new and desire to secure by Letters Patent:

l. In a multiple quick acting refrigerating system, a compressor, a high pressure condenser, a low pressure and low temperature condenser, a pipe connecting said two condensers, an expansion valve adjacent the entrance of the low pressure and low temperature condenser, a refrigerator or evaporator, a pipe connecting the low pressure condenser with the refrigerator or evaporator, anexpansion valve adjacent the entrance of the refrigerator, or evaporator, a pipe connecting the refrigerator or evaporator with the compressor, a pipe connecting the compressor with the high pressure condenser, and a closed refrigerating cycle, including a compressor, a condenser, an expansion valve and a refrigerating element adapted to cool the low temperature and low pressure condenser.

2. In a multiple quick acting refrigerating system, a'double evaporator containing two sets of refrigerating tubes, each set of said tubes being the refrigerator tubes of a closed refrigerating cycle, each cycle including a compressor, a concycles permitting the use of different refrigera pipe connecting the outlet of the pressure condenser tubes oi' the combinationy unit with one of the sets of the refrigerating tubes in the double evaporator, and another pipe line branching oil' said pipe and communicating with the entrance end of the other set of refrigerating tubes of the double evaporator, a compressor for each set of refrigerating tubes to draw oi'l' and recompress the refrigerant in the corresponding set of refrigerating tubes 'and a pipe line connecting each of said compressors with the entrance end of the high pressure condenser.

4. In a multiple quick acting refrigerating system a high pressure' condenser, a combination evaporator and lowpressure condenser, a pipe connecting the outlet end of the high pressure condenser with the. -inlet of the low pressure condenser tubes, an expansion valve in said pipe adjacent the inlet of the low pressure condensing tubes, a double evaporator, two sets of refrigeratting tubes arranged in said double evaporator, a pipe connecting the outlet of the low pressure condenser tubes in the combination evaporator and condenser tank with the inlet of one of the sets of the refrigerator tubes in the double rei'rlgerator, an expansion valve in this pipe adjacent inlet of said set of refrigerator tubes, a branch pipe leading from said pipe to the inlet of the secondset of refrigerating tubes in the double evaporator, an expansion valve in said branch pipe adjacent to inlet of the second set of refrigerator tubes, a compressor, a pipe connecting said compressor with the outlet end of the first set of refrigerating tubes, another pipe connecting the compressor with the inlet of the high pressure condenser, a second compressor adapted to draw oil.' the refrigerant vaporA oi! the second set of refrigerating tubes, a pipe connecting said second compressor with the pipe connecting the rst compressor and the inlet of the high pressure condenser, a bypath connecting the inlet pipe of the high pressure condenser-with the pipe connecting the high pressure and the low pressure condenser, a shut-oi! valve-inV the inlet pipe of the high pressure condenser arranged between the inlet to said condenser and the junction oi the bypath with the inlet pipe, and a .second shut-off valve in the pipe connecting thetwo condensers and located between the junction of the bypath with the said connecting pipe and the outlet of the high pressure condenser.

5. In a multiple quick acting refrigerating system a high pressure condenser, a combination unit containing a set of low pressure and 'low temperature condenser tubes, a pipe connecting the high pressure condenser with the low pressure condenser tubes. an expansion valve in said pipe adjacent the inlet of the low pressure condenser tubes, a double evaporator, two sets of refrigerating elements in said evaporator, a pipe connecting the outlet of the low pressure and low temperature condenser tubes with the inlet of one of the sets of the refrigerating elements, an

A denser element and an expansion valve, said expansion valve in said pipeline adjacent the inlet of the ilrst set of rei'rigerating elements, a pipe branching oi! from the pipe which connects the outlet of the low pressure condenser with the inlet of the first set o'f refrigerating elements,-

said branch leading into the inlet of the second set of refrigerating elements, a' compressor adapted to draw on and recompress the refrigerant vapor from the first set of reirigerating elements, a pipe connecting said compressor with the outlet of the first set of refrigerating elements, an-

other pipe connecting said compressor with theinlet of the high pressure condenser, a second compressor, a pipe connecting the outlet of the second set oi' refrigerating elements with said compressor, another pipe connecting the second compressor with the pipe leading into the inlet of the "high pressure condenser, a pipe connecting the two pipes leading from the outlets of the two sets of refrigerating elements and arranged before the two compressors, and a shut-off valve in each of said pipes behind the junction with the connecting pipe. A

6. In a multiple quick acting refrigerating system a high pressure condenser, a set of low pressure condenser tubes, a combination evaporator .and condenser unit containing said condenser tubes arranged in the combination evaporator l and condenser unit, a compressor adapted to draw of! refrigerant vapor from the refrigerating tubes, recompress the same and force it into the fresh water cooled condenser, a pipe line connecting the outlet-oi' said condenser with the inlet of the refrigeratingtubes, an expansion valve in. said pipe line adjacent the said inlet, a double evaporator, two sets of refrigerating tubes arranged in said evaporator, a pipe line connecting the low pressure and low temperature condenser tubes with the inlet of the first Set of refrigerating tubesin lthe double evaporator, an expansion valve in said pipe line adjacent the inlet of said refrigerating tubes, a branch pipe leading from said pipe line to the inlet of the second set of reirigerating tubes in the dmible evaporator, an expansion valve in said branch pipe, a second compressor adapted to draw refrigerant vapor oil the rst set of refrlgerating tubes in the double evaporator, a third compressor adapted to draw refrigerant vapor from the second refrigerating tubes in the double evaporator, a pipe connecting the second compressor with the corresponding refrigeratlng tubes, another pipe line leading from the compressor to the high pressure condenser, a fur.

ther pipe connecting the third compressor with the corresponding refrigerating tubes, a pipe connecting the third compressor with the pipe leading from the second compressor to the high pressure condenser, a cooling room, pipe lines leading from the double evaporator to the cooling room, the combination evaporator and condenser unit and back to the double evaporator, and a Apump adapted to circulate a fluid medium `inlet 0f the rst Sert of said tubes with the 011tthe second set of reiri'g'erating tubes, a second compressor, a pipe connecting said compressor with the outlet of the second set of refrigerating tubes, and another pipe line leading jfrom the second compressor to the second fresh water,J

cooled condenser. y

8. In a multiple quick acting refrigerating system a fresh water cooled condenser, a combination condenser and evaporator unit, a set of refrigerating tubes in said unit, a pipe line connecting the outlet of the fresh water cooled condenser with the inlet oi' the refrigerating tubes, a compressor, a pipe connecting the outlet of the refrigerating tubes with the compressor, another pipe leading from the compressor to the inlet of the fresh water cooled condenser, a high pressure fresh water cooled condenser, a set of low pressure condenser tubes in the combination condenser and evaporator unit, a pipe connecting the high pressure and the low pressure condenser,

an expansion valve in said pipe adjacent the inlet ofthe low pressure condenser tubes. a double evaporator, two sets of refrigerating tubes in said evaporator, a pipe connecting the outlet of the low pressure condenser with the inlet of the rst set of reirigerating tubes in the double evaporator, a branch pipe connecting this pipe with the inlet of the second set of the refrigerating tubes in the double evaporator, an expansion valve in said pipe adjacent the inlet of the said rst set of refrigerating tubes, a second expansion valve in the branch pipe adjacent the inlet of the second set of refrigerating tubes. a second compressor, a pipe connecting the outlet of the rst set of refrigerating tubes in the double evaporator with the second compressor, another pipe leadingfrom the second compressor to the inlet of the high pressure condenser, a third compressor. a pipe connecting said third compressor with the outlet of the second set of refrigerating tubes inthe double evaporator, another pipe leading from the third compressor to the inlet of the high pressure condenser, a valve interrupting the communication between the high pressure condenser and the low pressure condenser, a valve interrupting the connection between the iirst compressor and the outlet of the refrigerating tubes in the combination unit, a

valve preventing refrigerant from flowing out of the low pressure condenser tubes, the expansion valve adjacent the inlet of the refrigerating tubes in the combination unit being adapted to be closed, thereby making it possible to leliminate all the tubes .in the Ycombination unit, vs. pipe connecting vthe expansion valve adjacent the `inlet of the first set of tubes in fthe `i'loiible evaporator with the outlet of the ihigh vpressure condenser, and vanother pipe line connecting the outlet of the first fresh water cooled condenser with the expansion valve adjacent the second set of refrigerating tubes in the double evaporator.

9. In a multiple quick acting refrigerating sysstem a fresh water cooled condenser, a set of refrigerating tubes arranged in a combination evaporator and condenser unit, a compressor, a pipe connecting the outlet of said refrigerating tubes with the compressor and a pipe leading from said compressor to the inlet of the water cooled condenser, a double evaporator, two sets aneoo oi' refrigerating tubes in said double evaporator, a high pressure condenser, a set of low pressure condenser tubes in the combination unit, a pipe connecting the high pressure condenser with the low pressure condenser, an expansion valve in said pipe adjacent the inlet of the low pressure condenser, a pipe connecting the outlet of the low pressure condenser with the inlet of the first set of refrigerating tubes in the double evaporator, a branch pipe connecting this pipe with lthe inlet of the second set of refrigerating tubes in the double evaporator, a second compressor, a pipe connecting said compressor with the outlet of the iirst se't of refrigerating tubes in the double evaporator, another pipe leading from this compressor to the inlet of the high pressure condenser, a third compressor, a pipe connecting this compressor with the second set of refrigerating tubes in the double evaporator, a further pipe connecting the last named compressor with the inlet of the high pressure condenser, a valve adapted to interrupt the communication between the second compressor and the outlet of the rst set oi' refrigerating tubes in the double evaporator, another valve adapted to prevent communication between the third compressor and the second set of refrigerating tubes in the double evaporator, the two expansion valves adjacent the refrigerating tubes in the double evaporator being adapted to be closed so that the tubes in said double evaporator are adapted to be eliminated, a pipe adapted to be connected with the low pressure condenser pipes in the combination unit, and with one of the compressors adapted to be connected with one of the sets of refrigerating tubes in the double evaporator.

10. A refrigerating system comprising, in combination, a closed circuit including a compressor, a condenser. an expansion valve, and a refrigerator connected in series in the order named, a second closed circuit including a compressor, a condenser, an expansion valve, and a refrigerator connected in series in the order named, and means defining a refrigerator chamber, each refrigerator comprising inlet and discharge manifolds and a plurality of tubes connecting said manifolds, the tubes of said respective refrigerators being located in said chamber and extending crosswise of each other in intermingled relation.

11. A refrigerating system comprising, in coinbination, a closed circuit includingfa condenser, said circuit having t primary path and a secondary path and selectively available, said primary path including an expansion valve, a primary refrigerating element and a compressor in series, said secondary path including an expansion valve, a secondary refrigerating element and a compressor in series, and a second closed circuit including said ii-rst mentioned condenser and a f second condenser, said second. circuit having 'a second primary path and a second secondary path selectively available, said second primary path including an expansion valve, a second primary refrigerating element connected with said compressors, said second secondary path including an expension valve, a second secondary refrigerating element and a compressor in series, said primary refrigerating elements being incorporated in a refrigerating unit, said secondary reirigerating elements being incorporated in another refrigerating unit, whereby -both units may be combinedly operated or whereby either of said units with two cooling circuits is selectively available.

12. A. refrigerating system comprising, in combination, a condenser. a conduit tor liquid refrigerant operatively connected to the discharge of said condensers, auV evaporator unit having two independent rei'rigerating elements, said conduit having two discharge branches connected respectively to the inlets of said elements, two expansion valves one interposed in each of said branches, a conduit for refrigerant vapor con-v nected to the. inlet of said condenser, said last mentioned conduit having two inlet branches connected respectively to the discharge ends oi'l said elements, two compressors interposed respectively in said inlet branches, two stop valves interposed respectively in said inlet branches at the inlet sides of said compressors, andI a by-pass conduit including a stop valve forconnecting said inlet branches at the inlet sides of said nrst mentioned valves, whereby either or both oi said compressors may be` connected in the circuit.

13. A refrigerating system comprising', in combination, a condenser, a condenser and liquid cooler unit, a conduit connecting said condenser and said unit, a closed circuit including a refrigerating element, a compressor, a condenser and an expansion valve connected in series in the order named, said rei'rigeratlng element being arranged in heat exchange relation to said unit, a liquid discharge conduit opening from said unit, an evaporator unit having two separate refrigerating elements, said discharge conduit having two branches connected respectively to the inlets of said elements, two expansion valves one interposed in each of said branches, a conduit for vapor refrigerant'for connecting the discharge ends of said elements to the inlet of said first mentioned condenser, compressor means in said lastmentioned conduit, and means whereby the compressed refrigerant may be directly conveyed to the condenser and liquid cooler unit.

14. A refrigerating system comprising, in combination, a condenser, a condenser and liquid cooler unit, a conduit connecting said condenser and said unit, a closed circuit including'a refrigerating element, a compressor, a condenser and an expansion valve connected in series in the order named, said refrigerating element being arranged in heat exchange relation to said unit, a liquid discharge conduit opening from said unit, an evaporator unit having two separate refrigerating elements, said discharge conduit having two branches connected respectively to the inietsof said elements, two expansion valves one interposed in each of said branches, a conduit for vapor refrigerant connected to the inlet of said iirst mentioned condenser, said last mentioned conduit having inlet branches connected respectively to said elements, two compressors interposed respectively in said inlet branches, and a oy-pass conduit including a stop valve for connecting said rst mentioned conduit to said vlis-v charge conduit.

15. A refrigerating system comprising, in combination, a condenser, a condenser and liquid cooler unit, a. conduit connecting said condenser and said unit, a closed circuit including a refrigerating element, a compressor, a condenser and an expansion valve connected in series in -the order named, said refrigerating element being arranged in heat exchange relation to said unit, a. liquid discharge conduit opening from said unit, an evaporator unit having two separate refrigerating elements, said discharge conduit having Jtwo branches connected respectively to the inlets of said last mentioned elements, two expansion valves one interposed in each of said branches, a conduit for vapor refrigerant connected to the inlet of said rst mentioned condenser, said last mentioned conduit having inlet branches connected respectively to said last mentioned elements, two compressors interposed respectively ln said inlet branches, and a by-,pass conduit including a stop valve'i'or connecting said last mentioned conduit to said rst mentioned conduit.

16. A refi'igerating system comprising, in combination, a .primary condenser, a condenser and liquid cooler unit, a conduit connecting said condenser and said unit, two valves in said conduit.

duit, a stop valve interposed in said last mentioned conduit between said primary condenser and said compressor, a by-pass conduit, includinga stop valve, connecting said rst mentioned conduit at a point between said first mentionedA valves to said discharge conduit, and a by-pass conduit including a stop valve connecting said last mentioned conduit at a point between said ,compressor and said second mentioned stop valve to' said rst mentioned conduit at a point between said il-rst mentioned va1ves.

17. -A refrigerating system comprising, in combination, a water cooled condenser, a condenser andliquid cooler unit, a conduit connecting said condenser and said unit, a closed circuit including a refrigeratlng element, a compressor, a con- 40 denser and an expansion valve connected in series inthe order named, said refrigerating element being arranged in heat exchange relation to said unit, a liquid discharge conduit opening from said unitfanevaporator connected to said discharge conduitan expansion valve in said discharge conduit, a conduit for refrigerant vaporl connecting said evaporator to said iirst mentioned condenser, a compressor in said last mentioned conduit, and means whereby a fluid..

medium maybe circulated through said unit. n

18. A refrigerating system comprising, in combination, a water cooled condenser, a liquid cooler, a refrigerating circuit for cooling said cooler, a conduit connecting said condenser and said cooler, an evaporator, a cooling room, means for circulating a cooling medium from said cooling room through said cooler and said evaporator back to -said room, a conduit for liquid'refrigerant connecting the outlet of said cooler to said evaporator, an expansion valve in said last mentioned conduit, a conduit for vapor refrigerant connecting said refrigerator to the inlet of said condenser, a compressor in said last mentioned conduit, a by-pass conduit for connecting said rst mentioned conduit to said second mentioned conduit at the inlet side of said expansion valve, and a stop valve in said by-pass conduit.

19. A refrigerating system comprising, in combination, a condenser, a k,conduit for vapor refrigerant connected to the inlet of said condenser, a compressor in said conduit, a liquid cooler unit, a conduit connecting said condenser and .said unit, said unit including a cooling element connected to said last mentioned conduit, a pas-` pansion valve connected in series, whereby cold liquid medium from said passage and liquid refrigerant from said cooling element are available for outside use.

20. A refrigerating system comprising, in combination, a water cooled condenser, a conduit for vapor refrigerant connected to the inlet of said condenser, a compressor in said conduit. a stop valve in said conduit between said condenser and said compressor, a condenser and liquid cooler unit, a conduit connecting said condenser and said unit, a stop valve in said last mentioned conduit, a by-pass conduit for connecting' said first mentioned conduit at a point between said compressor and said first mentioned stop valve to said last mentioned conduit at a point between said last mentioned stop valve and said unit, a stop valve in said by-pass conduit, said unit comprising a cooling element connected to said second mentioned conduit, and a refrigeratingelement in heat exchange relation with said cooling element,

anda closed circuit including said refrigerating element, a compressor, a condenser, and an expansion valve connected in series.

2l. A refrigerating system comprising, in combination, a watercooled condenser, a liquid cooler. a conduit connecting said condenser and said'cooler. a cooling circuit including a refrigerating element, a compressor, a condenser, and an expansion valve connected in closed series, said refrigerating element being arranged in heat exchange relation to said cooler, a second cooler having a cooling element and a refrigerating element in heat exchange relation, a conduit for liquid refrigerant connected to the outlet of said first mentioned cooler, said last mentioned conduit having two discharge branches connected respectively to the inlets of said elements, an expansion valve interposed at the inlet of said last mentioned refrigeratingV element, an exhaust conduit connecting the outlet of said last mentioned refrigerating element to the inlet of said first mentioned condenser, and a compressor in said last mentioned conduit, said exhaust conduit having an inlet branch at the inlet side of said compressor vior the supply of refrigerant, whereby a portion of the liquid refrigerant from said first mentioned cooler is utilized to further cooi another portion of said liquid refrigerant available for outside use from said cooling element'.

22.^The process oil refrigeration which comprises compressing a refrigerant vapor of low boiling point, condensing the compressed refrigerant by the use of water as the cooling medium, further cooling the liquid refrigerant by the use of a cold vaporized refrigerant of higher boiling point as a second cooling medium, vaporizing a portion of the low boiling point liquid refrigerant, and utilizing said vaporized portion as a third cooling medium to further cool the remaining portion of the liquid refrigerant.

23. The process of refrigeration which comprises circulating a refrigerant through a closed path and in the course of circulation successively compressing. condensing and vaporizing said refrigerant, compressing a second refrigerant, utilizing the vaporized refrigerant to condense said second refrigerant, vaporizing a portion of said second refrigerant, and utilizing the .vaporized portion of said second refrigerant to further cool another portion of said second refrigerant.

24. In a refrigerating system, a housing defining a chamber, two refrigerating elements located in said housing, a' compressor, a condenser, and

an expansion valve connected with each of said elements to form two closed refrigerating circuits and each circuit permitting the use of a different refrigerant, said two circuits being operable singly or jointly.

25. In a condensing and cooling system of the character described for low temperature work comprising, in combination, a condenser, a conduit for a uid medium connected to said condenser, a cooler, a conduit connecting said rst condenser and said cooler, a secondary cooler, a conduit for connecting said coolers, a discharge conduit for the cooled medium connected to said secondary cooler, a second water cooled condenser, a discharge conduit connecting said second water cooled condenser with said first mentioned cooler, an expansion valve in said last mentioned discharge conduit, a by-pass conduit connecting said last mentioned discharge conduit and said secondary cooler, an expansion valve in said by-pass, a conduit for vapor refrigerant connecting said first mentioned cooler with said second mentioned condenser, and a compressor inserted insaid conduit, a second conduit for refrigerant vapor connecting said secondary cooler and said second mentioned condenser, a compressor inserted in said conduit, and means for conducting a medium to be condensed or cooled through said iirst mentioned condenser, said flrst mentioned cooler, and said secondary cooler whereby said cooled medium may be discharged. y

26. In a condensing and cooling system of the character described for low temperature work comprising, in combination, a condenser, a fluid medium conveying conduit connected to said condenser, a cooler involving a housing provided with independent controllable passages for the refrigerant medium and mediums to be cooled, a conduit connecting the condenser and said cooler, a secondary cooler involving a housing provided with independent controllable passages, a discharge conduit for the last mentioned cooler, a conduit for connecting one of the fluid medium passages of the two coolers, means for introducing the separate mediums to be cooled into both of said coolers, a closed refrigerating circuit involving the refrigerating element of the rst mentioned cooler, a compressor, a condenser and an expansion valve arranged in series, a by-pass for conveying a portion of the discharged refrig'- erant from said last mentioned condenser to the refrigerating passage of the secondary cooler, an expansion valve adjacent to said refrigerating passage, and an exhaust conduit leading from said last mentioned refrigerating passage to said second mentioned condenser and a compressor inserted in said exhaust conduit, the cooling passages oi' both of said coolers being provided with separate controllable inlets and outlets.

27. In a two stage refrigerating system employing two different refrigerants, a double evap orator unit with two closed separate refrigerating passages and a free passage for leading a medium to be cooled through said evaporator unit, two

compressors, two condensers, and two expansion valves connected with .the double evaporator unit in a prearranged manner to provide two closed refrigerating circuits which may be singly or jointly operated.

28. In a condensing' and cooling system oi' the character described, for low temperature work, a primary condenser. a primary cooler, and a secondary cooler, a closed refrigerating circuit, for cooling the primary cooler, consisting of a compressor, a condenser, an expansion valve and a primary refrigerating element, a second closed refrigerating circuit for cooling said secondary cooler, consisting of a compressor, said last mentioned condenser, an expansion valve, and a secondary refrigerating element, a controllable dis-v charge from the secondary cooler, said primary cooler and said primary refrigerating element being arranged in heat exchange relation with each other, and incorporated in a closed housing, said secondary cooler and said secondary refrigerating element being arranged in heat exchange relation with each other and incorporated in a housing, and means -for conducting a medium to be condensed and cooled through said primary condenser, said primary cooler, and said secondary cooler. Y

29. A refrigerating element comprising, in combination' a closed circuit, including two condensers, said circuit having a primary path and a secondary path, said primary path including an expansion valve, refrigerating elements and a compressor in series, said secondary path includ-l ing an expansion valve, refrigerating elements and a compressor in series, and a second closed circuit including said condensers, said second circuit having a secondprimary path and a second secondary path and selectively available, said second primary path including an expansion valve, a second primary refrigerating element and one of said mentioned compressors in series. said second secondary path including an expansion valve, a second secondary refrigerating element and a compressor in series, the'refrigerating elements of the nrst circuit being incorporated in an evaporator unit, the refrigerating elements of the second circuit being incorporated in another evaporator unit, whereby either one or both of said units with two cooling circuits is available.

30. In a multiple refrigerating system having two condensers, a combined evaporator and liquid cooler unit, a plurality of expansion valves. and a plurality of compressors and an evaporator and a cooling room interconnected to form a plurality of refrigerating circuits, the method of refrigerating which consists of expanding and vaporizing a liquid refrigerant from one of said condensers in the combined evaporator and liquid cooler unit to refrigerate said unit, precool the liquid refrigerant from said other condenser in the combined evaporator and liquid cooler unit and expanding and vaporizing the main part of said precooled liquid refrigerant in said mentioned evaporator, commingle the other part of said precooled liquid with the liquid of said first mentioned condenser before expanding the same in the evaporator and liquid cooler unit to increase thefiiciency of said unit, recompress the expanded and vaporized refrigerants and returning the same back to the condensers to liquefy the same again, leading a medium to be cooled through said evaporator to abstract heat therefrom, utilizing the cooled medium to wol said cooling room. passing the medium from said cooling room first through said mentioned evaporator and cooler unit to abstract heat from said medium and then returning the same to the evaporator to further cool said medium.

3l. In a multiple refrigerating system for low temperature and quick freezing work having a condenser. a.triple passage cooler unit, a conduit connecting said condenser and said unit, a

closed refrigerating circuit consisting of acomv presser, a condenser. an-expansion valve and one of said passages of said cooler unit to expand a .refrigerant therein to refrigerate said cooler unit,

a double evaporator. a liquid refrigerant discharge conduit connecting/said cooler unit and said double evaporator, a second discharge conduit connecting said first mentioned condenser and said nrst mentioned discharge conduit in order to mingle the liquid refrigerant from said discharge conduits before entering said double evaporator, two exhaust discharge conduits connecting the evaporator with the first mentioned condenser, and compressor means inserted in said last mentioned exhaust discharge conduits, a cooling room, pipe lines connecting said triple passage unit,.said double 'evaporator and said cooling room, and means for circulating the cooling medium in a closed cycle through saidcooling room, said triple passage cooler unit and said' double evaporator. v l

32. In a multiple refrigerating system for low temperature and quick freezing work having a condenser, a triplepassage cooler unit, a conduit connecting said condenser and said unit. a closed refrigerating circuit consisting of a compressor, a condenser, an expansion valve and one of said passages of said triple passage cooler unit to expand a refrigerant therein, to refrigerate said cooler unit; a double evaporate a liquid refrigerant discharge conduit connecting said cooler unit and said double evaporator, a second discharge conduit connecting saidilrst mentioned condenser and said ilrst mentioned discharge conduit in order to mingle the liquid refrigerant from said discharge conduit before entering said double evaporator, two exhaust discharge conduits connecting the evaporator with the ilrst mentioned condenser, compressor means inserted in said last mentioned discharge conduits, pipe, lines connecting said triple passage cooler unit and said double evaporator, and means for leading a medium to be cooled through said cooler unit and said double evaporator.

33. In a multiple refrigerating system, the combination of a compressor, a condenser, a liquid cooler, a double evaporator unit, expansion means for said unit, pipe lines connecting said elements in the order named, connections between the double evaporator, means whereby the refrigerant vapor from its first path through said double evaporator is directed through the second path in said double evaporator and said exhaust thence directed through said liquid cooler and drawn from said liquid cooler by said compressor and thence returned to said condenser.

34. A process of refrigeration which consists in expanding a liquid refrigerant in one path of a double` evaporator unit, leading the exhaust with a drop in pressure through the second path of said double evaporator unit, expanding the exhaust from the second path with an additional vdrop in pressure into a liquid cooler to precooi the initially incoming refrigerant, recompressf ing the gaseous refrigerant and reliquefying the same.

35. A multiple quick acting refrigerating SYS- tem, comprising a condenser; a combined gas and liquid cooler having separate paths, a double evaporator unit, a compressor. an expansion valve at the inlet of one of the refrigerating eie- -ments of said 'double evaporator unit. controllable pipe lineebetween the liquid discharge end of thecombinedgasand liquidcooler andtheiniet of one of the refrigerating elements of s aid double evaporator unit. connections between the dis charge end of the first mentioned elementof the double evaporator unit and the second element of said unit. a by-pass between the discharge end of said second element andthe inlet of the second path in said combined gas and liquid cooler, in combination with a closed circuit involving said nrst mentioned comprsor, a second condenser, an expansion valve and the second mentioned path in the combined gas and liquid cooler whereby the exhaust from the evaporator and vaporised liquid refrigerant fromsaid last mentioned second condenser is itilised in said combined gas and liquid cooler. and means whereby the exhaust from the combined gas and liquid cooler is returned to the ilrst mentionedy condenser and to said second mentioned con- 36In a multiple 4quick acting refrigerating system, the process of refrigerating which consists in expanding a condensed liquid refrigerant in a cooler having a multiple of paths. compressing and condensing a second refrigerant. cooling the second refrigerant in one of the paths in said cooler to a low temperature, expanding the low temperature liquid refrigerant in an evaporator, commingling and expanding a part of .the second low temperature liquid refrigerant with the first mentioned liquid refrigerant to increase the eiiiciency in thevflrst path and recompressing the expanded refrigerants and recondensing the same. leading a medium in contact with the second refrigerant path. utilizing the cooled medium for outside use and then passing said medium through another path in said cooler to precool the medium and then returning the same into contact with-the second mentioned low temperature refrigerant path to further cool said medium.

37. In a refrigerating system of the character described, a primary condenser, a secondary condenser and an evaporator, arranged in a closed 4of! through said liquid cooler in part or in full 3l. In a condensing and cooling system of the character described having a water cooled condenser, a primary cooler, a secondary cooler. connected in the order named, a second condenser. liquid refrigerant discharge conduits connecting s, said primary cooler? and said secondary cooler, liquid refrigerant expansion means for lboth of said coolers to control the pressure orvacuum and the temperature in said coolers. conduits and compressor means arranged to -draw off the vaporlzed refrlgerants and to return them to the second mentioned condenser: and means for leading a fluid medium to be condensed or cooled, through said iirst mentioned condenser, said primary cooler and said secondary cooler. n

39. In a refrigerating system a condenser, a combined gas and liquid cooler unit having a refrigerant evaporating element. a conduit connecting said condenser and said unit, means for introducing a refrigerant gas under pressure into l0 said condenser to condense the same, separate means for introducing a refrigerant gas" of temperature lower than said aforementioned gas into said unit,k said liquid cooling element in said unit being adapted to cool the liquid from said condenser and said gas at the same pressure, and means for withdrawing liquid refrigerant from said unit.

40. In a refrigeratlng system, comprising compressor means; a condenser; a liquid cooler; a refrigerator or evaporator, connected in the order named; valve controlled exhaust discharge conduits'arrangements whereby the exhaust from said refrigerator or evaporator. may be drawn 3s by the compressor meansxor the exhaust from the refrigerator or evaporator may be drawn olf in part or in full directly by the compressor means.

4l. In a refrigerating system, a condenser, a combined gas and liquid cooler unit provided with a refrigerating element connected with said' condenser; an expansion valve for said refrigerating element: arrangements whereby liquid refrigerant from said condenser may be supplied to said refrigeratlng element; means for withdrawing the vaporlzed refrigerant from said element and to return the same to the condenser; a second condenser connected with said unit; means whereby compressed gas is introduced into the second mentioned condenser to be liquefied; means for introducing compressed gas into said unit, whereby said gas and the liquid from said secondmentioned condenser are mingled and further condensed and cooled at constant pressure in said unit: and a liquid discharge conduit for 55 said unit.

` AUGUST SCHWARZ. 

